1. Field of the Invention
This invention relates in general to sign apparatus, and relates in particular to emergency sign apparatus within a building required by law to indicate an exit.
2. Description of the Related Art
There are a variety of signs used in buildings to provide emergency exit signs. These signs are made of a variety of materials, including various metals and plastics, which are mounted on a building ceiling or wall. There are a number of objections to this arrangement. A sign mounted on a wall is subject to damage from a variety of sources, which can even include vandalism. Further, architects consider these signs to be objectionable in appearance. These signs are produced in many different directional arrow configurations that require excessive production of various configurations and can result in potential mistakes in shipping. The proper configuration for any information could be solved by a universal field modified sign adaptable to any configuration. It would be desirable if an exit sign could be concealed completely within a wall or ceiling and still provide the required information, since such an arrangement would eliminate all of the above objections.
This invention provides a sign, which is mounted completely within the surface of a wall or ceiling, which projects the desired message on an adjacent surface including a wall, the ceiling or a suspended surface.
The sign information is displayed by projecting the desired message on the surface. The projected message is obtained by directing a light source through image forming apparatus. Typical image forming apparatus can include replaceable image lens or stencil. The projection apparatus is mounted within a telescoping tube having three sections. The outer end of the first section mounts the light source and an adjacent image forming apparatus. The second center section, and the third section each mount a lens at the light entrance end. The lenses are arranged such that changing the overlap of the first and second section will change the size of the resulting projected image, and changing the overlap of the second and third section will change the focus of the resulting projected image. The second and third sections have indices along their exterior to respectively indicate the overlap of the first and second sections and the overlap of the second and third sections. Both the overlapped first and second section, and the overlapped second and third section can be locked together at various amounts of overlap.
When the image forming apparatus is a stencil, the stencil is pivotably mounted across the tube cross-section. Opposed projections from the stencil apparatus extends through opposed slots in the tube. A scale around one of the slots and the relationship of the projections to the slots indicates the angular relationship of the stencil to a perpendicular pair of axis which are contained in a plane perpendicular to the tube axis. This information assists in orienting the projected image relative to the receiving surface, which will be described further later.
The adjacent planar surfaces receiving the image are normally inclined with respect to the projection apparatus. The adjacent surfaces can be a wall, the ceiling or a suspended surface. The mounting apparatus for the tube mounts the tube within a circular opening at an angle with respect to the surface of a wall or ceiling. An outwardly extending flange, which has a central opening, is the only part of the mounting apparatus which is external to the opening.
The mounting apparatus is symmetrical about the mounting hole, which permits the apparatus to be mounted at any angle around a line perpendicular to the flange opening. This permits the tube to be mounted with the projected image directed to either the right or left side, upward or downward, or at any angle in between. This permits directing the projected image on an adjacent side wall, the ceiling, or on a suspended surface. Because of the circular dimensions, only a single, relatively small size, circular hole is required to mount both the bracket and projection apparatus.
The first section has a light source located at its outer end, with the image forming apparatus mounted adjacent to the light source. The second and third section each have a lens mounted across their respective light entrance ends. Although any image forming means can be used, as indicated above it can be a stencil. The tube is installed at an angle with respect to the wall opening to permit projecting an image upon an inclined adjacent wall, ceiling or suspended surface.
In use, the mounting apparatus is oriented and the tube angle adjusted such that the projected image is directed onto the desired adjacent surface. The lenses are then adjusted by changing the relationship between the tube sections to focus the image upon this surface with the required size and the tube sections are locked relative to each other to maintain this desired relationship.
Since this apparatus is primarily intended to be used to indicate an exit, it is important that a power line failure not interrupt the projection of the image. The following two back-up power supply arrangements, among other similar arrangements, could be provided to essentially eliminate the possibility of a power interruption. Both would provide direct current power to the light source.
One power supply arrangement could use both a trickle charger and battery combination and a separate battery charger, with both being powered by a conventional alternating power source. The battery charger would provide direct current power to the light source and the trickle charger would maintain the battery at full charge. In the event of a power failure a relay could be used to open the battery charger circuit, disconnect the trickle charger from the battery and connect the battery to the light source to provide continuous direct current power for operation.
Another power supply arrangement could use a conventional alternating current power source and a back-up alternating current power source. Here the back-up could be either an engine-generator combination, or a battery-inverter combination with either providing alternating current of the same frequency and voltage as the conventional source, and arranged to turn on automatically upon failure of the conventional power source. A relay would switch from the conventional power source to the back-up source upon power failure, such that either of the above back-up power source arrangements would provide system power. A battery charger, which would normally be connected to the conventional power source, upon failure of the conventional power system, would be switched by a relay to the back-up source, such that either active source would provide direct current power to the light source.
Providing a back-up power supply arrangement similar to either of those described above, would insure that the projected message would probably never be interrupted.
Since the message is provided by projection, it can be made any desired size. Further, since a back-up power source arranged as those described above, could be provided for the event of a power line failure, it is extremely unlikely that there will ever be a failure in displaying the message. The total concealment of the sign apparatus, with only the exception of the flange, eliminates the problems with previous signs as to their vulnerability to damage and their appearance.